As far as conductivity, silver is the best. Followed by copper, the gold.The THICKNESS of the conductor is important as to frequency, as lower frequencies penetrate the conductor much deeper than high frequencies.(Thus a silver plated copper conductor for video actually carries the entire signal in the silver layer. Where a similar cable carrying audio freq. the signal is penetrating through into the copper (especially the lower ones), and screwing the signal up.The study may have had some meaning, but I doubt it applies to audio cables!!

IMO, it only makes sense if you are "tri-amping", otherwise an audio cable carries EVERY frequency 0 to over 20KHz. And even with tri-amping (say with a Linn system), I kinda doubt too many 'philes would have different metal IC's for each band....

With regard to normal(not freq. dependent) conductivity: Without getting too technical(for simplicity's sake) call the best metal conductor, silver, 100% conductive. Copper(2nd best) comes in only about 5% less conductive, while gold is 25% less conductive(than silver and just ahead of aluminum). A combination of conductors(outside of silver/copper) would create more problems than it solved. What Elizabeth is referring to is called "skin effect". The higher freqs travel toward the outside or skin of the conductor(causing a higher resistance than the lower freqs toward the center), with freq abberations and time/phase smear results. That's why Litz type wire has become popular in audio. Lots of smaller conductors(individually insulated), that allow all the freqs contained in the signal to arrive at the end of the wire coherently and intact. The Litz solution has been applied for years from tonearm wiring to speaker cables(and, of course, there are the unbelievers). I fully agree that the "results" of that "study" are suspect. The effect of the Rubidium would only be be appreciated by your local bats or Early Warning Radar System anyway. A bit more info on skin effect: (http://en.wikipedia.org/wiki/Skin_effect)

Personally, I think this whole topic is BS. As those of us in this niche of the hobby tend to be more on the subjectivist side, if anything like this study existed, we would have most probably been hit over the head with it so many times that we'd all be parroting it.

As a former material scientist/chemist, I think he is probably mistaking rubidium for either rhodium or ruthenium, both of which are among the 8 precious metals. It makes little sense to plate a precious metal (silver) with a non-precious one (rubidium), but commonplace to plate non-precious metals (copper, nickel, etc.) with precious metals (silver, gold, rhodium...).